Dubal installs UAE's first steam unit chiller

Dubai, March 30, 2013

The UAE’s first-ever steam absorption chiller installation in a power plant has been inaugurated at Dubai Aluminium (Dubal), a major state-owned aluminium smelter, as part of an innovative pilot project using steam.

A quest for continuous improvement coupled with a determination to optimise organisation’s energy consumption levels has led to Dubai Aluminium (Dubal) achieving another pioneering milestone, said a company statement.

On this occasion, the corporation has leveraged a nominal volume of the steam produced by the captive cogeneration and combined cycle Dubal power station to drive the UAE’s first-ever absorption chiller using waste heat; and the first such application in a power plant.

Built on the rooftop of Dubal’s Desalination Plant Control Building, the new absorption chiller has assumed the functions formerly fulfilled by the electrically-driven vapour compression air-conditioning chillers used for comfort cooling of the building, said Tayeb Al Awadhi, the VP (Power & Desalination) Dubal, the statement added.

"The absorption chiller uses high vacuum conditions to lower the boiling point of water to 3.7˚C (versus 100˚C at atmospheric pressure) while leveraging the chemical affinity of Lithium Bromide (LiBR) to absorb water," explaines Al Awadhi.

"At this low temperature, highly concentrate Lithium Bromide (LiBr) absorbs the water vapour given off in the boiling process very effectively. As the LiBr becomes dilute, its capacity to absorb water vapour reduces. A heat source is required to re-concentrate the LiBr – whether steam, flue gases or even hot water," he stated.

"In Dubal, steam generated from waste energy was utilised. Heating causes the solution to release the absorbed water vapour, which is then cooled in a separate chamber to become a liquid refrigerant (in the form of chilled water) through condensation. The process uses just 40 per cent of the electricity consumed by the conventional electrically-driven chillers and uses a nominal 0.6 tonnes of steam per hour to produce sufficient cooling for the same purpose,” he added.

Al Awadhi said Dubal’s new absorption chiller has the capacity to reduce the corporation’s energy consumption by approximately 626,800 kWh per year. Based on the standard conversion factor, this equates to a reduction in CO2 generation by about 350 tonnes per year, also equivalent to an estimated 180 cars off the road per year.

“Installing this first absorption chiller was a pilot project, targeted at demonstrating the concept’s ability to save energy and protect the environment,” stated Al Awadhi.

“The concept can also be used for other applications where energy-efficient cooling is required – such as equipment cooling,” he added.

Al Awadhi pointed out that the absorption chiller project was a great example of Dubal’s on-going focus on energy-savings, which has seen the corporation invest approximately Dh457 million ($124 million) on energy-efficiency projects since 2005.

Dubal's absorption chiller was officially inaugurated by its president and CEO Abdulla Kalban during a special ceremony on Wednesday in the presene of selected guests from the Dubai Supreme Council of Energy (DSCE), of which Dubal is a member.

Commenting on the project, Kalban said, "This absorption chiller is expected to reduce the auxiliary power consumption of the Dubal plant, thus offering broader economic and environmental benefits to the business."

"It will also add real value by using readily available steam from our Power and Desalination Plants without compromising the processes of either,” he added.-TradeArabia News Service